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mktemp(3) Library Functions Manual mktemp(3) NAME mktemp, mkstemp - Construct a unique filename LIBRARY Standard C Library (libc.so, libc.a), System V Compatibility Library (libsys5.a) SYNOPSIS Standard C Library #include <stdlib.h> int mkstemp( char *template); char *mktemp( char *template); STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: mktemp(), mkstemp(): XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. PARAMETERS Points to a string to be replaced with a unique filename. The string in the template parameter must be a filename with six trailing Xs. DESCRIPTION The mktemp() function replaces the contents of the string pointed to by the template parameter with a unique filename. The application must initialize template to be a filename with six trailing Xs; mktemp() re- places the Xs in the template string with a unique filename. Under libc.a, the filename is a unique combination of the thread name and process ID. Under libsys5.a, the filename is created with the getpid function. The mkstemp() function performs the same substitution to the template name and also returns a file descriptor for the file open for reading and writing. The function thus prevents any possible race condition be- tween testing whether the file exists and opening it for use. The mk- stemp() function is not available under libsys5.a. RETURN VALUES Upon successful completion, the mktemp() function returns the address of the string pointed to by the template parameter. If the string pointed to by the template parameter contains no Xs, or if the mktemp() function is unable to construct a unique filename, the first character of the template parameter string is replaced with a null character, and a null pointer is returned. Upon successful completion, the mkstemp() function returns an open file descriptor. If the mkstemp() function fails, it returns a value of -1. ERRORS No errors are defined for this routine. RELATED INFORMATION Functions: tmpfile(3), tmpnam(3), getpid(2) Standards: standards(5) delim off mktemp(3)